Related Party Transactions - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013 Maximum [Member]	Dec. 31, 2012 Maximum [Member]
Related Party Transaction [Line Items]
Accounts payable, related parties					$ 0.1	$ 0.1
Distribution and administration expenses	$ 0.2	$ 0.7	$ 0.4	$ 1.4